Not applicable.
The present invention relates to an apparatus for the application of chemicals to vegetation, and in particular, to a direct-contact apparatus for the application of herbicide to undesired vegetation without disturbing desired vegetation.
Efficient methods of weed control are essential in order to maximize crop yield using modem agricultural techniques. Weeds are most easily eliminated through the effective use and application of chemical herbicides. Costly herbicides must be applied efficiently. So-called xe2x80x9cselectivexe2x80x9d herbicides contain chemical agents formulated for use with specific types of vegetation. In contrast, non-selective herbicides contain an active chemical agent which kills all vegetation with which it comes into contact. Such non-selective herbicides are therefore less expensive to produce than selective herbicides, and may effectively kill all forms of undesirable weeds. However, in applying non-selective herbicides, care must be taken to apply the chemicals in a manner that targets weeds alone, and not valuable crops.
A common method for applying herbicides is direct spraying. Spraying of herbicides suffers from the disadvantages of requiring relatively heavy and expensive equipment. Also, non-selective herbicides can not be applied using this technique because both crops and weeds would be affected. Even when selective herbicides are used, spraying still significantly wastes the herbicide as it is applied on both the crops and the weeds. Thus, efficient use of non-selective herbicides requires a system that minimizes waste and provides for a uniform, controlled application.
A relatively new method of weed control that is particularly suited for this purpose is a direct contact application technique, using a so-called xe2x80x9cwick applicatorxe2x80x9d. Wick applicators are an example of direct contact applicators which directly apply the herbicide to weeds by rubbing an absorbent wick-like structure saturated with herbicide onto the weeds. Wick applicators are advantageous to use since comparatively new xe2x80x9csystemicxe2x80x9d herbicides, as opposed to traditional conventional herbicides which burn vegetation, may be used with such applicators. After contact, a systemic herbicide is absorbed by the vegetation and permeates the root systems to kill weeds without affecting the soil.
Mechanisms which employ wick applicators mounted to farming vehicles that traverse crops and apply herbicides through a wiping action are known. Due to the variety of crops, a wick applicator""s particular structure is dictated by the size, layout, and density of the weeds relative to the crops. Since many weeds tend to initially outgrow crops in the early stages of growth, several direct contact applicators have been developed to take advantage of this differential in plant height. For example, devices in which a wiper bar is mounted to a hydraulic positioning assembly adjusted to conform to the nominal height of weeds while remaining above the crops growing below are known. However, crops which outgrow the nominal height of the weeds are subject to destruction by the applicator mechanism coming into physical contact therewith. This technique is also inherently inefficient in that it targets weeds relatively late in their growth cycle, in which the weeds have already diverted a significant amount of soil nutrients from the crops.
Also, in applying herbicide in a wiping action, the amount of herbicide applied is a function of the time in which the herbicide-saturated wick is in contact with weeds as the apparatus traverses the field. To increase this contact time, devices which take advantage of vertical wick positioning have been proposed. These devices provide structures in which the angular orientation of the wick with respect to the direction of travel of the tractor allows for greater contact time. However, these devices suffer from the disadvantage of using rope-shaped wicks with a low relatively low contact surface area and thus a low contact time.
Another shortcoming of the known structures is that they fail to work when applied to crops with furrows, or spaces between rows of plants. To effectively target weeds in furrows before they have appreciably grown, direct contact applicators must conform to the particular shape of the furrows. Known devices use a deformably rigid wick applicator of annular shape with a relatively low contact surface area. This arrangement is disadvantageous because the applicator must be manually deformed to conform to the particular shape of different furrows. The manual deformation requirement results in a relatively low contact time with the weeds, the failure to contact and apply chemicals to the weeds and undesired contact with seeded areas and wanted vegetation.
Thus, it is desirable to have an apparatus for applying chemicals to vegetation, in particular non-selective herbicidal chemicals, which is suitable for use in furrows having varying cross-section, and which has sufficient flexibility so as to closely conform to the contours of the furrows. It is further desirable to provide a large applicator contact surface area to apply the chemical to the weeds. And it is further desirable to provide an injection system to uniformly distribute chemical in a controlled and efficient manner from a supply source onto the applicator surface.
The present invention advantageously provides a system for applying a chemical, such as an herbicide, to a surface. For example, the system provided by the present invention makes the application of a non-selective herbicide to undesired vegetation growing in a furrow efficient, cost effective and convenient.
One aspect of the present invention provides a chemical applicator apparatus for applying a chemical from a chemical supply source to a surface, in which an intake manifold has at least one fluid receiving opening and at least one fluid distribution opening. Each fluid receiving opening receives a chemical flow from the chemical supply source and each fluid distribution opening distributes the received chemical flow. At least one planar interface element is in fluid communication with a respective fluid distribution opening. Each planar element receives the chemical flow from the fluid distribution opening. At least one wick sheet is coupled to and is in fluid communication with the at least one planar interface element. Each wick sheet absorbs the chemical flow from the at least one planar interface element and applies the chemical flow to a surface in contact with the wick sheet.
As another aspect, the present invention provides a system for applying a chemical to a surface, in which a chemical reservoir storing a quantity of chemical for dispensation to the surface is provided. A flow control unit is in fluid communication with the chemical reservoir, and includes a conduit in which the chemical flows from the chemical reservoir through to at least one wiper assembly. The flow control unit is adjustable to control the rate of chemical flow in the conduit. Each wiper assembly is in fluid communication with the flow control unit. At least one wick sheet is coupled to the wiper assembly. Each wick sheet absorbingly receives the chemical from the flow control unit and wipingly applies the chemical to the surface.
As yet another aspect, the present invention provides a chemical applicator apparatus for applying a chemical from a chemical supply source to a surface. The applicator comprises a frame, at least one wick assembly coupling member, and a plurality of wick assemblies. Each wick assembly coupling member has a first end portion adjustably coupled to the frame, and a second end portion opposite the first end portion. Each wick assembly is individually coupled to the second end portion of the wick assembly coupling member. The plurality of wick assemblies are in fluid communication with the chemical supply source, each wick assembly wipingly applying the chemical to the surface.